break
				}
			}

			if !found {
				t.Errorf("altNames does not contain DNSName %s", DNSName)
			}
		})
	}

	expectedIPAddresses := []string{"1.2.3.4", "127.0.0.1", net.IPv6loopback.String(), proxyIP}
	for _, IPAddress := range expectedIPAddresses {
		t.Run(IPAddress, func(t *testing.T) {
			found := false
			for _, val := range altNames.IPs {
				if val.Equal(netutils.ParseIPSloppy(IPAddress)) {

		t.Skip("both IPv4 and IPv6 are required")
	}

	for _, tt := range []struct {
		network string
		lit     string
		addr    *TCPAddr
	}{
		{"tcp4", "::1", nil},
		{"tcp4", "", &TCPAddr{IP: IPv6loopback}},
		// We don't test the {"tcp6", "byte sequence", nil}
		// case for now because there is no easy way to
		// control name resolution.
		{"tcp6", "", &TCPAddr{IP: IP{0x01, 0x23, 0x45, 0x67, 0x89, 0xab, 0xcd, 0xef}}},

	}

	// create AltNames with defaults DNSNames/IPs
	altNames := &certutil.AltNames{
		DNSNames: []string{cfg.NodeRegistration.Name, "localhost"},
		IPs:      []net.IP{advertiseAddress, net.IPv4(127, 0, 0, 1), net.IPv6loopback},
	}

	if cfg.Etcd.Local != nil {
		if certName == kubeadmconstants.EtcdServerCertName {
			appendSANsToAltNames(altNames, cfg.Etcd.Local.ServerCertSANs, kubeadmconstants.EtcdServerCertName)

// IPv6LinkLocalAllRouters returns the IPv6 link-local all routers multicast
// address ff02::2.
func IPv6LinkLocalAllRouters() Addr { return AddrFrom16([16]byte{0: 0xff, 1: 0x02, 15: 0x02}) }

// IPv6Loopback returns the IPv6 loopback address ::1.
func IPv6Loopback() Addr { return AddrFrom16([16]byte{15: 0x01}) }

// IPv6Unspecified returns the IPv6 unspecified address "::".
func IPv6Unspecified() Addr { return Addr{z: z6noz} }

	logger := klog.FromContext(ctx)
	primaryFamily := v1.IPv4Protocol
	nodeIPs := map[v1.IPFamily]net.IP{
		v1.IPv4Protocol: net.IPv4(127, 0, 0, 1),
		v1.IPv6Protocol: net.IPv6loopback,
	}

	if len(rawNodeIPs) > 0 {
		if !netutils.IsIPv4(rawNodeIPs[0]) {
			primaryFamily = v1.IPv6Protocol
		}
		nodeIPs[primaryFamily] = rawNodeIPs[0]
		if len(rawNodeIPs) > 1 {

	}
	in := &CertificateRequest{
		DNSNames:       []string{"example.com", "example.org"},
		EmailAddresses: []string{"******@****.***", "******@****.***"},
		IPAddresses:    []net.IP{net.IPv4(192, 0, 2, 0), net.IPv6loopback},
		URIs:           []*url.URL{urlA, urlB},
	}
	out := marshalAndParseCSR(t, in)

	if !reflect.DeepEqual(in.DNSNames, out.DNSNames) {

		{"IPv4len", Const, 0},
		{"IPv4zero", Var, 0},
		{"IPv6interfacelocalallnodes", Var, 0},
		{"IPv6len", Const, 0},
		{"IPv6linklocalallnodes", Var, 0},
		{"IPv6linklocalallrouters", Var, 0},
		{"IPv6loopback", Var, 0},
		{"IPv6unspecified", Var, 0},
		{"IPv6zero", Var, 0},
		{"Interface", Type, 0},
		{"Interface.Flags", Field, 0},
		{"Interface.HardwareAddr", Field, 0},
		{"Interface.Index", Field, 0},

pkg net/http, type Transport struct, OnProxyConnectResponse func(context.Context, *url.URL, *Request, *Response) error #54299
pkg net/netip, func IPv6LinkLocalAllRouters() Addr #51766
pkg net/netip, func IPv6Loopback() Addr #51777
pkg net, type Dialer struct, ControlContext func(context.Context, string, string, syscall.RawConn) error #55301
pkg os/exec, type Cmd struct, Cancel func() error #50436

pkg net, var IPv4bcast IP
pkg net, var IPv4zero IP
pkg net, var IPv6interfacelocalallnodes IP
pkg net, var IPv6linklocalallnodes IP
pkg net, var IPv6linklocalallrouters IP
pkg net, var IPv6loopback IP
pkg net, var IPv6unspecified IP
pkg net, var IPv6zero IP
pkg net/http, const DefaultMaxHeaderBytes ideal-int
pkg net/http, const DefaultMaxIdleConnsPerHost ideal-int